Processing玩抠图

突然兴起想玩一下抠图，试着用自带的Example\video来改，花了一个中午做了个小样：

分别是白色为底与黑色为底的效果，代码如下：

 import processing.video.*;
 int numPixels;
 int[] backgroundPixels;
 Capture video;
 PImage img;

 void setup() {
   size(640, 480);
   video = new Capture(this, width, height);
   video.start();
   numPixels = video.width * video.height;
   backgroundPixels = new int[numPixels];
   img = new PImage(video.width, video.height);//make a copy of video.
   frameRate(30);
 }

 void draw() {
   if (video.available()) {
     video.read();
   }
   img = video;//use img as a template
   img.loadPixels();
   for (int i = 0; i < numPixels; i++) {
     color currColor = img.pixels[i];
     color bkgdColor = backgroundPixels[i];
     int currR = (currColor >> 16) & 0xFF;
     int currG = (currColor >> 8) & 0xFF;
     int currB = currColor & 0xFF;
     int bkgdR = (bkgdColor >> 16) & 0xFF;
     int bkgdG = (bkgdColor >> 8) & 0xFF;
     int bkgdB = bkgdColor & 0xFF;
     int diffR = abs(currR - bkgdR);
     int diffG = abs(currG - bkgdG);
     int diffB = abs(currB - bkgdB);
     int td = 20;//set threshold to 20 pixcels;

     //check each pixel of the frame, set background pixels to white.
     if (diffR >td||diffG>td||diffB>td) {
       img.pixels[i] = color(currR, currG, currB);
     } else {
       img.pixels[i] = color(255, 255, 255);
     }
   }
   img.updatePixels();
   //use mouse to adjust the blur effect;
   fastblur(img,(int)map(mouseX,0,width,1,20));
   //display image.
   image(img, 0, 0);
 }

 void keyPressed() {
   if (key == ' ') {
     arraycopy(img.pixels, backgroundPixels);
   }
 } 

 void fastblur(PImage img,int radius){

   if (radius<1){
     return;
   }
   int w=img.width;
   int h=img.height;
   int wm=w-1;
   int hm=h-1;
   int wh=w*h;
   int div=radius+radius+1;
   int r[]=new int[wh];
   int g[]=new int[wh];
   int b[]=new int[wh];
   int rsum,gsum,bsum,x,y,i,p,p1,p2,yp,yi,yw;
   int vmin[] = new int[max(w,h)];
   int vmax[] = new int[max(w,h)];
   int[] pix=img.pixels;
   int dv[]=new int[256*div];
   for (i=0;i<256*div;i++){
      dv[i]=(i/div);
   }

   yw=yi=0;

   for (y=0;y<h;y++){
     rsum=gsum=bsum=0;
     for(i=-radius;i<=radius;i++){
       p=pix[yi+min(wm,max(i,0))];
       rsum+=(p & 0xff0000)>>16;
       gsum+=(p & 0x00ff00)>>8;
       bsum+= p & 0x0000ff;
    }
     for (x=0;x<w;x++){

       r[yi]=dv[rsum];
       g[yi]=dv[gsum];
       b[yi]=dv[bsum];

       if(y==0){
         vmin[x]=min(x+radius+1,wm);
         vmax[x]=max(x-radius,0);
        }
        p1=pix[yw+vmin[x]];
        p2=pix[yw+vmax[x]];

       rsum+=((p1 & 0xff0000)-(p2 & 0xff0000))>>16;
       gsum+=((p1 & 0x00ff00)-(p2 & 0x00ff00))>>8;
       bsum+= (p1 & 0x0000ff)-(p2 & 0x0000ff);
       yi++;
     }
     yw+=w;
   }

   for (x=0;x<w;x++){
     rsum=gsum=bsum=0;
     yp=-radius*w;
     for(i=-radius;i<=radius;i++){
       yi=max(0,yp)+x;
       rsum+=r[yi];
       gsum+=g[yi];
       bsum+=b[yi];
       yp+=w;
     }
     yi=x;
     for (y=0;y<h;y++){
       pix[yi]=0xff000000 | (dv[rsum]<<16) | (dv[gsum]<<8) | dv[bsum];
       if(x==0){
         vmin[y]=min(y+radius+1,hm)*w;
         vmax[y]=max(y-radius,0)*w;
       }
       p1=x+vmin[y];
       p2=x+vmax[y];

       rsum+=r[p1]-r[p2];
       gsum+=g[p1]-g[p2];
       bsum+=b[p1]-b[p2];

       yi+=w;
     }
   }
 }

代码主要分为2个部分：

1. main

获取摄像头帧video，使用PImage对象img作为缓存帧，通过空格保存对比帧background，使用阀值将对比帧与缓存帧之间相同的部分存为指定颜色（例如：白色、黑色），再显示不同的部分。

2. fastblur

简单高斯模糊，本来是想进行边缘柔化的，结果发现这种方法不行，看来只有另外找了。